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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 86-102页

作者： G.kovács the Ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor Squirrel cage rotor Space harmonics Synchronous parasitic torques

Nonstationary laser-supported ionization wave in layer of porous substance with subcritical density

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Matter and Radiation at Extremes 2024年第1期9卷 58-70页

作者： S.Yu Gus’kov R.A.Yakhin P.N.Lebedev Physical Institute of Russian Academy of Sciences Leninskii Prospect 53Moscow 119991Russia

A time-dependent analytical solution is found for the velocity of a plane ionization wave generated under nanosecond laser pulse action on the surface of a flat layer of low-Z porous substance with density less than the critical density of the produced *** corrections for the two-dimensional nature of the problem when a laser beam of finite radius interacts with a flat target,this solution is in quantitative agreement with measurements of ionization wave velocity in various *** solution compared with experimental data covering wide ranges of performance conditions,namely,(3-8)×10^(14)W cm^(−2)for laser pulse intensity,0.3-3 ns for pulse duration,0.35-0.53μm for laser wavelength,100-1000μm for laser beam radius,380-950μm for layer thickness,4.5-12 mg cm^(−3)for average density of porous substance,and 1-25μm for average pore *** parameters of the laser beam that ensure the generation of a plane ionization wave in a layer of subcritical porous matter are determined for the problem statements and are found to meet the requirements of practical applications.

关键词： laser pulse porous

How to explore a new environment:exploratory tactics of the black rat(Rattus rattus)

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Current Zoology 2024年第3期70卷 371-382页

作者： IvetaŠtolhoferová Veronika Rudolfová Hana Skalíková Barbora Vobrubová Daniel Frynta Department of Zoology Faculty of ScienceCharles UniversityViničná712843 Prague 2Czechia

The black rat(Rattus rattus)is a unique model for studying exploratory tactics due to its enormous colonizing *** behavioral variability and consistent interindividual differences might help populations inhabit new environments and persist there even under intense pres***,the affnity of the black rat for climbing might be another advantage,widening their potential *** this study,we describe the exploratory tactics of the black rats when introduced to a novel *** the frst experiment,we tested 12 rats and calculated repeatability of their behaviors across 12 sessions of an enriched open-feld *** concluded that climbing is a highly repeatable behavior that serves as an important source of interindividual *** the second experiment,we tested 24 black rats in a unique L-shaped *** rat was tested *** found that the majority of rats distributed their activity evenly,exploring each part of the apparatus for a similar amount of time,thus maximizing their chances of fnding ***,these“even”explorers still greatly differed in their level of activity,orderliness and affnity for climbing,generating large *** contrast,the minority of rats concentrated their activity only on a section of the new environment and were therefore characterized as selective ***,we concluded that a combination of such exploratory tactics as well as a bias for even explorers enables black rats to quickly colonize new environments and persist there even under unfavorable conditions.

关键词： 3D behavior climbing repeatability strategy.

Weak influence of natural vegetation in urban green spaces compared to agricultural ecosystems on House Martin populations:Insights from nationwide citizen science data in the Czech Republic

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Avian Research 2024年第2期15卷 139-146页

作者： Denisa Dvorakova Jan Sipos Josef Suchomel Department of Zoology FisheriesHydrobiology and ApicultureMendel University in BrnoZemedelska 161300BrnoCzech Republic

The House Martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in ***,it is not yet sufficiently explained why this long-term decline *** fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House Martins on the landscape scale by using nationwide citizen science *** a generalised linear mixed-effect model(GLMM),we evaluated 12,094 records from the Czech Republic spanning *** analysis underscores the significance of land cover type in shaping House Martin *** specifically,our results indicate that within agricultural land covers“naturally managed arable lands”exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House Martin *** urban land covers,we found a clear distinction in the impact on House Martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House *** advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House Martin populations.

关键词： Citizen science Habitat preferences House Martin Species distribution Urban and suburban landscape

Trade-Offs and Synergie Effects of Regulating Ecosystem Services along an Climatic Gradient in Slovakia

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Journal of Geoscience and Environment Protection 2024年第6期12卷 135-150页

作者： Jarmila Makovníková Stanislav Kološta Boris Pálka National Agricultural and Food Centre Soil Science and Conservation Research Institute Bratislava Regional Station Bansk Bystica Bansk Bystrica Slovakia Faculty of Economics Matej Bel University Bansk Bystrica Slovakia

This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We evaluated ecosystem services based on biophysical indicators using an expert scoring system that determines the corresponding soil functions and is part of the existing databases available in Slovakia. This methodological combination enabled us to provide unique mapping and assessment of ecosystem services within Slovakia. Correlation analysis between individual regulating ecosystem services and climate regions, slope, texture, and altitude confirm the statistically significant influence of climate and slope in all agricultural land, arable land, and grassland ecosystems. Statistically significant synergistic effects were established between the regulation of the water regime and the regulation of soil erosion within each climate region, apart from the very warm climate region. Only in a very warm climate region was potential of regulating ecosystem services mutually beneficial for soil erosion control and soil cleaning potential (immobilization of inorganic pollutants).

关键词： Agroecosystem Services Climatic Zone Mapping Trade-Offs Synergies

In vivo and in vitro study of resorbable magnesium wires for medical implants:Mg purity,surface quality,Zn alloying and polymer coating

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Journal of Magnesium and Alloys 2024年第6期12卷 2472-2488页

作者： K.Tesar J.Luňácková M.Jex M.Žaloudková R.Vrbová M.Bartoš P.Klein L.Vištejnová J.Dušková E.Filová Z.Sucharda M.Steinerová S.Habr K.Balík A.Singh Department of Materials Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueTrojanova 13Prague 12000Czech Republic Institute of Physics Czech Academy of SciencesNa Slovance 2Prague 18221Czech Republic Institute of Dental Medicine First Faculty of MedicineCharles University and General University Hospital in PragueKaterinská32Prague 12801Czech Republic Department of Physics Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueBrehová7Prague 11519Czech Republic Department of Composites and Carbon Materials Institute of Rock Structure and MechanicsCzech Academy of SciencesV Holešovickách 41Prague 18209Czech Republic Institute of Anatomy First Faculty of MedicineCharles UniversityU Nemocnice 3Prague 12800Czech Republic Biomedical Center Faculty of Medicine in PilsenCharles UniversityAlej Svobody 76Pilsen 32300Czech Republic Department of Pathological Physiology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Department of Histology and Embryology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Institute of Pathology First Faculty of MedicineCharles University and General University Hospital in PragueStudnickova 2Prague 12800Czech Republic Department of Biomaterials and Tissue Engineering Institute of PhysiologyCzech Academy of SciencesVidenska 1083Prague 14200Czech Republic Research Center for Structural Materials National Institute for Materials Science1-2-1 SengenTsukuba 305-0047Japan

Magnesium is an excellent material in terms of biocompatibility and its corrosion products can serve as an active source for new bone ***,localized corrosion and H_(2)generation limit the potential of Mg-based *** low-alloyed Mg-Zn wires can strongly reduce problems with large H_(2)bubbles and improve the mechanical properties considerably while maintaining excellent long-term *** pickling and a polymer coating can be effectively used to lower the rate of in vivo *** this work,microstructural,mechanical,and in vitro characterization of 250μm and 300μm extruded wires made from ultra-pure Mg,commercially pure Mg,Mg-0.15Zn,Mg-0.4Zn and Mg-1Zn was ***,Mg-0.4Zn wires together with a variant coated with a copolymer of L-lactide andε-caprolactone were tested in vivo on artificially damaged Wistar rat *** on the observed Mg-induced osteogenesis,polymer-coated Mg wires with a small addition of Zn are a perspective material for bone-support applications,such as cerclage and fixation wires.

关键词： Magnesium Resorbable Mg wire Mg-Zn implant degradation Biocompatibility study Zn grain boundary segregation

Harmonics in the Squirrel Cage Induction Motor Analytic Calculation-Part Ⅰ: Differential Leakage, Attenuation, Asynchronous Parasitic Torques

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中国电工技术学会电机与系统学报(英文) 2023年第4期7卷 320-329页

作者： G.kovács Ganz Electric Works 1095 BudapestHungary

The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynchronous parasitic torques have been discussed in great detail in the literature, but always separately, for a long time. However, systematization of the phenomenon still awaits. Therefore, it is worth summarizing the completeness of the phenomena in a single study – with a new approach at the same time-in order to reveal the relationships between them. The role of rotor slot number is emphasized much more than before. An existing, commonly used, but still impractical basic figure has been modified to more clearly demonstrate the response of the rotor for the harmonics of the stator. The need to treat differential leakage, asynchronous parasitic torques and attenuation together will be demonstrated: new formula for asynchronous parasitic torque is derived;the long-used characteristic curves for differential leakage and attenuation used separately so far was merged into one, correct curve in order to provide a correct design guide for the engineers.

关键词： Asynchronous parasitic torque Attenuation Differential leakage Squirrel cage induction motor Winding harmonics

Laser-driven electrodynamic implosion of fast ions in a thin shell

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Matter and Radiation at Extremes 2023年第5期8卷 73-81页

作者： S.Yu.Gus’kov Ph.Korneev M.Murakami P.N.Lebedev Physical Institute of Russian Academy of Sciences 53 Leninskii Prospect119991 MoscowRussian Federation Institute of Laser Engineering Osaka University565-0871 OsakaJapan

Collision of laser-driven subrelativistic high-density ion flows provides a way to create extremely compressed ion conglomerates and study their *** paper presents a theoretical study of the electrodynamic implosion of ions inside a hollow spherical or cylindrical shell irradiated by femtosecond petawatt laser *** propose to apply a very effective mechanism for ion acceleration in a self-consistent field with strong charge separation,based on the oscillation of laser-accelerated fast electrons in this field near the thin *** electrons are generated on the outer side of the shell under irradiation by the intense laser *** is shown that ions,in particular protons,may be accelerated at the implosion stage to energies of tens and hundreds of MeV when a sub-micrometer shell is irradiated by femtosecond laser pulses with an intensity of 10^(21)–10^(23)W cm^(−2).

关键词： dynamic thin irradiated

Associative learning in plants:light quality history may matter

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BIOCELL 2022年第3期46卷 645-649页

作者： FATIMA CVRČkovÁ HANA KONRÁDOVÁ Department of Experimental Plant Biology Faculty of ScienceCharles UniversityPragueCZ 12843Czech Republic

The possibility of associative learning in plants is a topic of ongoing *** one published study,growing pea plants were reported to associate two stimuli(airflow and light)and thereafter use one(airflow)as an indicator for the other(light),similar to dogs in Pavlov’s famous ***,this observation could not be independently *** we examine a possible reason for the failure of a published reproduction attempt,which used substantially different light quality during plant cultivation prior to experimental treatments than in the original *** could have resulted in dramatically different growth *** the relevance of the original report of plant associative learning remains questionable,greater attention should be paid to good documenting and standardizing the light conditions,in particular spectral quality,not only in studies of plant learning and memory,but also in other areas of experimental plant biology.

关键词： Classical conditioning Light quality Phototropism Replicability Reproducibility

Isomorphisms of Cubic Cayley Graphs on Dihedral Groups and Sparse Circulant Matrices

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Acta Mathematica Sinica,English Series 2023年第4期39卷 618-632页

作者： Istvan kovACS UP IAM&FAMNIT University of PrimorskaMuzejski trg 26000 KoperSlovenia

We show that,up to isomorphism,there is a unique non-CI connected cubic Cayley graph on the dihedral group of order 2n for each even number n≥*** answers in the negative the question of Li whether all connected cubic Cayley graphs are CI-graphs(Discrete Math.,256,301-334(2002)).As an application,a formula is derived for the number of isomorphism classes of connected cubic Cayley graphs on dihedral groups,which generalises the earlier formula of Huang et *** with the particular case when n is a prime(Acta ***.,***.,33,996-1011(2017)).As another application,a short proof is also given for a result on sparse circulant matrices obtained by Wiedemann and Zieve(arXiv preprint,(2007)).

关键词： Cayley graph graph isomorphism dihedral group circulant matrix